HIV-1 Nef has many functions that work to enhance the pathogenicity of HIV and SIV which are important for the progression to AIDS. One such function is the enhancement of infectivity of virions that contain the Nef gene. Various investigators have shown an array of effects on virion infectivity from changes in cholesterol content of virions (a producer cell effect) to proposed effects on the process of reverse transcription (a target cell effect). Unfortunately, many of these studies have been done using different viruses and different cell systems and the conclusions have not always been directly comparable. The goal of this project will be cells, virions, and target to investigate the potential effects of Nef on producer cells in the same project. We will take advantage of several unique approaches that have been developed in our lab to study the effects of Nef in three contexts: 1. Nef expressed in producer cells, but containing mutations that prevent incorporation into virions. 2. Nef directly delivered to virions by fusion of virions with secreted Nef vesicles. 3. Nef-GFP labeled virions to allow tracking of Nef after fusion and entry. Completion of these experiments will allow us to better understand at which stages of the viral life cycle Nef can exert an effect on infectivity. A better understanding of how Nef modulates virion infectivity would provide the basis for developing therapeutics based on this mechanism. In light of the difficulties in finding an effective vaccine, a better understanding of the basic functions of Nef and other viral proteins could provide an alternative to control viral infectivity. In the past decade the search for an HIV/AIDS vaccine has been more difficult than anyone would have anticipated. To date, the production of new antiviral drugs has provided the greatest success we have had in reducing deaths due to AIDS. Therefore, it is important to continue to study basic viral replication in the effort to find new antiviral strategies. The goal of this project is to advance our understanding of how the HIV virus controls its own infectivity. PUBLIC HEALTH RELEVANCE: With support from the Kirschstein fellowship, I aim to prepare ultimately for a meaningful and prolific career in academia or being an adept researcher at the National Institutes of Health or Centers for Disease Control studying minority health disparities. The research training proposed in this application will greatly facilitate achievement of this long-term goal in a number of ways. First, it will facilitate acquisition of various technical skills (e.g. cloning, immuno-cytochemistry) which will certainly prove Instrumental in post-doctoral work. Secondly, and perhaps more importantly, accomplishment of this training will foster the development of the critical thinking skills required for independent research. Moreover, support from this fellowship and training program will allow me to attend conferences and present my work, thus promoting effective communication skills.